Blood platelets play a critical role in the prevention of excessive blood loss at sites of tissue injury. They are formed from megakaryocytes in the bone marrow and circulate in the bloodstream in a quiescent state, but undergo 'explosive'activation upon damage to the vasculature, supporting formation of a vascular plug. Conditions associated with a reduction in platelet number (thrombocytopenia) or function can lead to excessive bleeding. Platelets play a fundamental role in thrombotic disorders, including stroke and myocardial infarction, and contribute to the metastatic spread of cancer. As such, platelets are a major target for pharmaceutical intervention, both to enhance production and block function. Despite this clinical significance, there are major gaps in our understanding of the molecular events which underlie platelet formation and activation. Research in this area had been hampered by the paucity of megakaryocytes in marrow, and the challenges of growing these cells in vitro with the generation of large numbers of platelets. The availability of genetically-modified mice, the discovery of thrombopoietin and the introduction of powerful technologies such as genomics, proteomics and RNAi has triggered a revolution in terms of molecular progress. However, until the current Gordon Research Conference was convened 4 years ago, there was no focused meeting that brought together scientists working on megakaryocyte and platelet cell biology. This third conference on 'The Cell Biology of Megakaryocytes and Platelets'will bring together academic and pharmaceutical investigators, post-doctoral fellows and graduate students for 5 days of intense discussion of the major scientific discoveries and challenges in the field at the GRC site in Galveston Island, TX March 15-20th, 2009. This application is a request for partial funds to support the attendance of speakers and discussion leaders, and selected postdoctoral fellows and students at this important scientific meeting. This meeting will be held at: Hotel Galvez 2024 Seawall Boulevard Galveston Island, TX 77550